1. Field of the Invention
The present invention relates to a magnetic device, and more particularly to a choke with high saturation current and low core loss.
2. Background of the Invention
A choke is one type of magnetic device used for stabilizing a circuit current to achieve a noise filtering effect, and a function thereof is similar to that of a capacitor, by which stabilization of the current is adjusted by storing and releasing electrical energy of the circuit. Compared to the capacitor that stores the electrical energy by an electrical field (electric charge), the choke stores the same by a magnetic field.
FIG. 1A illustrates a conventional choke with a toroidal core. However, a traditional choke with a toroidal core requires manual winding of the wire coil onto the toroidal core. Therefore, the manufacturing cost of a traditional choke is high due to the high labor cost.
In addition, chokes are generally applied in electronic devices. Recent trends to produce increasingly powerful, yet smaller chokes have led to numerous challenges to the electronics industry. In particular, when the size of a traditional choke with a toroidal core is reduced to a certain extent, it becomes more and more difficult to manually wind the wire coil onto the smaller toroidal core, and the choke can no longer produce a desired output at a high saturation current.
FIG. 1B illustrates a conventional sealed choke with a ferrite core. However, the sealed choke cannot produce a desired output at a high saturation current. In addition, it also becomes more and more difficult to wind the wire coil onto the ferrite core when the size of the sealed choke shrinks to a certain extent.
FIG. 1C illustrates a conventional molding choke with an iron-powder core. However, the iron-powder core has a relatively high core loss. In addition, since the wire coil is placed in the mold during the molding process and the wire coil cannot sustain high temperature, it is not possible to perform an annealing process to reduce the core loss of the molded core after the molding process.
In view of the above, how to reduce the manufacturing cost and minimize the size of the chokes while still keeping the features of high saturation current and low core loss at heave load becomes an important issue to be solved.